Abstract
Introduction
Although surgical remedies tend to be the long-term solutions for patients with osteoarthritis (OA), many alternatives exist that offer the potential to slow progression, alleviate pain, and/or restore function. One such option is the unloader OA knee brace. The objective of this study was to assess the in vivo medial joint space narrowing with and without the brace during weight-bearing portion of gait.
Methods
Twenty subjects were evaluated after being clinically assessed by a single surgeon to be bone-on-bone on the medial side. In vivo gait kinematics were collected using a validated 3D-to-2D fluoroscopic registration technique (Figure 1). Subjects were asked to first walk on a treadmill without a brace (Figure 2), and then, after a qualified technician fit a properly sized brace to each subject, they were asked to walk again (Figure 3). In vivo fluoroscopic images were captured and registered at heel-strike (HS) and mid stance (MS) for both scenarios. CT scans were used to acquire the patient-specific bone models that were used in the registration process.
Results
All twenty subjects experienced a positive increase in medial joint space and verbally stated their knee pain lessened while wearing the brace. The average medial joint space change was 1.7±0.8 mm (3.1 max, 0.3 min) at HS and 1.6±0.8 mm (3.7 max, 0.4 min) at MS (Figure 4). Five patients experienced more than 2.5 mm of medial joint space change when wearing the unloader brace, indicating substantial effectiveness of the brace.
Conclusion
While previous unloader brace studies have focused on outcome scores and patient satisfaction to analyze brace effectiveness, this study quantifiably demonstrated improvement in joint space narrowing due to the unloader brace. These results suggest that unloader braces may provide benefit in the interim when symptoms of OA are present prior to need for surgical intervention.
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